Journey in the microscopic world
Division of matter: can it be done indefinitely?
What are the basic constituents of matter?
19th century: atoms are considered as basic entities
many type of atoms: H, He, Li, C, O, Al, Fe,…….
the known atoms combine to create complex molecules
the great variety of substances are a result of different combination of a few type of atoms
Ordering the atoms after their weight
(Dmitri Mendeleev: periodic table of the elements)
- periodic properties of atoms
- atoms can be arranged in a table,
where each column has similar
chemical and physical properties.
Existence of periodicity: a
clue that there might be an
underlying structure to atoms ….